The Competition & Markets Authority has updated the administrative timetable for the publication of its provisional determination on Price Review appeals by five water companies against Ofwat’s Final Determinations on their AMP8 business plans.

Six water companies rejected Ofwat’s final determinations and asked Ofwat to refer them to the CMA for a redetermination. Ofwat referred the appeals by Anglian Water, Northumbrian Water, South East Water, Southern Water and Wessex Water to the CMA in March 2025.

Originally scheduled for 23 September 2025, the CMA now anticipates publication of its provisional determination for the five companies in early October 2025.

The CMA said it will consider what updates may be required to the administrative timetable in due course, noting that its overall statutory deadline of 17 March 2026 remains the same.

The adminstrative timetable is currently as follows:

• Early-October 2025 Publish provisional determinations
• Mid-October 2025 Deadline for responses to provisional determinations
• Mid-December 2025 Target for issue of reports to Ofwat and publication of summary
• Mid-January 2026 Target for publication of final determinations
• 17 March 2026 Statutory deadline (with extension) for final determinations

In February Thames Water also requested a referral to the CMA, but then asked Ofwat for the formal reference to the CMA to be deferred for a period of up to 18 weeks.

On 18 March 2025 Thames announced that it had agreed with Ofwat that the regulator would defer making the referral for a period of up to 18 weeks. Ofwat said at the time that this reflected the company’s view that further discussions could result in steps that would unlock a market-led solution for the recapitalisation of the company, including through an equity raise, without the need for the reference to the CMA.

In July Ofwat subsequently agreed to a request from Thames Water to further defer the referral of its PR24 Final Determination to the CMA for a re-determination until 22nd October 2025.

Thames Water and investors say CMA approach to current referrals should not prejudice or predetermine any redetermination by CMA in relation to Thames 

Notwithstanding its own referral, Thames Water made a Third Party Submission in April to the CMA in response to the five disputing companies’ Statements of Case.

In June the water company and investors in Thames Water both made separate submissions to the CMA commenting on the document published on 28 May setting out the approach and prioritisation the Authority intended to take to its redetermination. Both stressed the importance that the CMA approach document related only to the other five companies.

The investors’ submission paper states that the CMA’s approach in these cases must not pre-empt any future redetermination for Thames Water in relation to PR24.

“Each case should be considered on its own facts and legal arguments. We consider this is particularly important for water companies experiencing serious financial distress. The Investor Group reserves its rights to make further submissions including in the following areas in the event of a Thames Water redetermination,” the paper says.

The paper submitted by Thames Water says that the company agrees with a “significant proportion” of the points raised by the disputing companies. However, it goes on to caution:

“As the CMA will be aware, Thames Water is experiencing well-publicised operational and financial difficulties, and we are in the process of turning our business around and attracting new capital and deliver on our business plan. We are also subject to region-specific challenges and costs by virtue of operating in London and which, as the interim report by the Independent Water Commission, recognises are not reflected in Ofwat’s current approach which “places excessive reliance on econometric modelling based on (largely historic) sectoral benchmarking”.

“Thames Water considers that it is imperative, particularly noting the exceptional nature of the company’s present position, that it is clear that the CMA’s approach to, and consideration of, the issues for the five disputing companies does not in any way prejudice or predetermine any redetermination by the CMA in relation to Thames Water.”